...Blasting is the process where small angular or spherical particles are propelled at a part by compressed air, or mechanical high speed rotating wheels or water pumps. The blast

BLASTING TECHNICAL INFORMATION

The reference in surface TreaTmenTwww.istsurface.com


2Blasting Technical Informations

TABLE OF CONTENTS

BLAST FINISHING ................................................................................................................................................................................... 3

FACTORS THAT AFFECT BLAST FINISHING .................................................................................................................................. 4

FACTORS THAT AFFECT BLAST FINISHING (CONT’d) .............................................................................................................. 5





ALL INdUSTRIAL BLAST SYSTEMS HAVE THE FOLLOWING COMPONENTS : .................................................................. 9

BLAST MEdIAS ....................................................................................................................................................................................... 10

BLAST MEdIAS (CONT’d) ................................................................................................................................................................... 11




BLAST MEdIAS (ENd) .......................................................................................................................................................................... 15

HOW TO MEASURE SURFACE PROFILE USING TESTEx TAPE ............................................................................................... 16

OUR MISSION ......................................................................................................................................................................................... 17



BLAST FINISHING

Blasting is the process where small angular or spherical particles are propelled at a part by compressed air, or mechanical high speed rotating wheels or water pumps.

The blast media type, shape, size, density, and hardness, along with media acceleration and volume of media, combined with blasting distance from the workpiece, angle of impact and time cycles are important factors in the blast process capabilities.

The blasting equipment is produced to deliver, reclaim and contain the media, contain the part to be blasted and collect the dust from the blasting process. Parts can be processed individually as a batch process or can be automated thru the system.

surface affecTs from The blasTing process are :

visual

bright matte finish

Dull matte finish

satin finish

satin luster finish

blending of tool marks

removal of weld discoloration

surface cleaning

glass frosting and etching

pre plate and anodize finishes

mechanical

Deburring

De-flashing

paint and coating removal

peening

pre paint and coating adhesion

heat treat, mill scale removal

Weld splatter removal

Thermal metal spray preparation

rust removal

mold cleaning



meDia DeliverY sYsTems

There are three media delivery systems that propel and deliver media for high speed impact to the part being processed :

Air Blasting (Pneumatic) Mechanical Wheel (Airless blasting) Hydro blasting (Pumped water)

Air blAsting

utilizes an air compressors energy to deliver air/media mix at speeds and volumes to impact the parts being processed.

The air speed or pressure of an air compressor is controlled by a pressure regulator. The regulator can increase or decrease the speed of the media delivery. Air pressure is measured by pounds per square inch (psi), industrial blasting is effectively done between 20 and 90 PSI. The higher the PSI the higher the air speed.

The volume delivered of the air/media mix is determined by the orifice or opening diameter of the nozzle with pressure blast systems or air jet diameter of the suction blast gun body. Air volumes are measured by surface cubic feet per minute (scfm). The larger the orifice Id opening the larger volume of air/media. Other factors that affect volume of air into the blast system is media and air hose diameter. Increased air pressure (PSI) also increases the SCFM with a given size orifice.

Industrial blasting gun bodies of suction cabinet blast systems range between 12 to 38 SCFM. The pressure blast cabinet systems range between 12 to 68 scfm and the pressure blast room systems use up to 254 scfm.

Industrial air compressors produce approximately 4.5 SCFM per horse power (hp). Blasting cabinets require 3 to15 hp compressors per nozzle and blast rooms can use up to 53 h.p. per man or nozzle.

There are TWo TYpes of air blasT DeliverY sYsTems :SUCTION (used in blast cabinets)PRESSURE (used in blast cabinets, blast rooms, and outdoor blasting)

suction

Blasting uses the venture principle sucking media from a hopper. The air jet is 1/2 the ID of the nozzle and as the air stream is passed through both, it creates a suction which sucks the media from the hopper into the air stream. The media acceleration distance is very short ( from the nozzle to the workpiece (approximately 4 to 14”). The suction system works fine and can continuously blast as long as there is blasting media in the hopper. Suction systems have limits on their suction capacity and on propelling heavier media. Very heavy blasting media (larger steel media) cannot be conveyed into the air stream with suction blasting. However, most industrial blast cabinets use suction systems due to their lower cost and because work well for most applications.

FACTORS THAT AFFECT BLAST FINISHING



Pressure

The pressure pot contains the media, and as it is energized with compressed air, it pressurizes the pot. When the air/media mix is released from the pot, it accelerates from the pot through at least 5-10 feet of hose and then even faster as it travels through the Venturi of the nozzle. The acceleration rates of air/media mix are much higher in pressure blasting than suction blasting. When the pressure pot empties of the media, it has to be depressurized to refill the pot with media. The pressure blasting systems are much more productive than suction systems. Pressure systems can blast all medias regardless of their weight or size, but they require a minimum of 25 psi to operate.

air blasT sYsTems - air consumpTion raTes

Below are charts of air volume (SCFM) used in blasting with pressure and suction systems utilizing various pressures (PSI) and orifice sizes.

cabineT blasT sYsTems - air reQuiremenTs (scfm)

Suction SyStemS PreSSure SyStemS

FACTORS THAT AFFECT BLAST FINISHING (CONT’d)

Pressure (psi) 30 40 50 60 70 80 90 100

1/4” nozzle 3/32 jet 6 7 8 10 11 12 13 15

1/4” nozzle 1/8 jet 10 12 15 17 19 21 23 26

5/16” nozzle 5/32 jet 15 19 23 27 31 37 38 42

7/16” nozzle 7/32 jet 31 38 45 52 59 66 73 80

Pressure (psi) 20 30 40 50 60 80 100 120

1/8” nozzle 6 8 10 13 14 17 20 25

3/16” nozzle 15 18 22 26 30 48 45 55

1/4” nozzle 27 32 41 49 55 68 81 97

5/16” nozzle 42 50 64 78 88 113 137 152

3/8” nozzle 55 73 91 109 126 161 196 220



blasT rooms anD ouTDoor sYsTems - air reQuiremenTs

Air consumption and media delivery rates are much higher on blast rooms and outdoor blasting systems than in pressure blast cabinets. The air supply hose ID, the media blast hose ID, the nozzle ID, the pressure pot and pot piping are all much larger on the blast rooms than cabinet systems. The increase in production is also due to the further distance that the nozzle is from the work piece in blast rooms creating a larger blast pattern.

Pressure-blAst requirements (blAst rooms)


pressure

nozzle iD 60 70 80 90 100 120

3/16’’ #3

air (cfm) 30 33 38 41 45 -/-

air compressor hp 7 7.5 8 9.5 10 -/-

lbs sand hour 171 196 216 238 264 -/-

1/4’’ #4

air (cfm) 54 61 68 74 81 97

air compressor hp 12 13.5 15 16.5 18 21.5

lbs sand hour 312 354 406 448 494 582

5/16’’ #5

air (cfm) 89 101 113 126 137 152

air compressor hp 20.0 22.5 25.5 28.0 30.5 34.0

lbs sand hour 534 604 672 740 812 912

3/8’’ #6

air (cfm) 126 143 161 173 196 220

air compressor hp 28 32 36 38.5 44 49

lbs sand hour 754 864 960 1 052 1 152 1 320

7/16’’ #7

air (cfm) 170 194 217 240 254 300

air compressor hp 38 43.5 48.5 53.5 56.5 67

lbs sand hour 1 023 1 176 1 312 1 448 1 584 1 800

1/2’’ #8

air (cfm) 224 252 280 390 338 392

air compressor hp 50 56 62.5 69 75 87.5

lbs sand hour 1 336 1 512 1 680 1 856 2 024 2 352



cabineT blasT proDucTion raTes

Below is an estimate of abrasive delivery rates per hour and sq. ft. of blast area in sq. ft. per minute with various orifice I.D’s and 80 psi.

air blasT proDucTion raTes

Blast nozzle spray patterns are affected by orifice size, air pressure, and distance from the workpiece.

The total diameter of the blast pattern increases as the distance from the workpiece is increased. The hot spot (where work speed is maximized) can be obtained at larger distances from the workpiece with pressure air blast systems.

CABINET SUCTION BLASTING CABINET PRESSURE BLASTING


iD cfm psi blast area (sq. ft/minute) abrasive unit hour

3/32’’ 7 80 1/2 80 lbs1/8’’ 15 80 1 to 1-1/2 120 lbs

5/32’’ 25 80 1 to 2-1/2 160 lbs3/16’’ 40 80 3 to 3-1/2 216 lbs1/4’’ 80 80 4 to 4-1/2 400 lbs

Nozzle

Spray diame-Spray diame-

*Standard Nozzle *Standard Nozzlehot spot hot spot

Hot Hot Brush-off Brush-off

brush-off brush-off

Distance from Workpiece Distance from Workpiecegun nozzle iD



blasT room anD ouTDoor blasT proDucTion raTes

mechanical Wheel blasTing

For more information on blast specifications contact [email protected]

blasT specificaTions (approx. sq. ft. cleaning per hour at 90 psi)

esTimaTeD blasT cleaning raTes (#7 nozzle)

no.1 WhiTe meTal blasT

sspc-sp5 #7 NOzzLELoose Mill Scale 170 Sq. Ft Tight Mill Scale 140 Sq. Ft

Pitted Paint 85 Sq. Ft. Layered Paint 70 Sq. Ft.

no.2 near WhiTe blasT



no.3 commercial blasT

sspc-sp6 #7 NOzzLE

Loose Mill Scale 420 Sq. Ft Tight Mill Scale 270 Sq. Ft


no.4 brush - off




Wheel blast system utilizes a high speed rotation wheel using centrifugal force to propel the media. The wheel size design and rotation speed affect the velocity and pattern of the media.The abrasive is fed into the rotating wheel. The impact on the media by the hard rotating wheel usually restricts media selection to a very tough steel or stainless steel shot or grit.Machines can be built with multiple wheels for automation. Automated systems include basket, table, spinner hangers and continuous conveyor processing.Wheel blast systems are a less expensive way to blast (due to higher media recycleability and automation) than air blasting by a factor of 10. Their disadvantage are restrictions to very few media.

Media Loading



hYDro blasTing


ALL INdUSTRIAL BLAST SYSTEMS HAVE THE FOLLOWING COMPONENTS :

This blasting system uses a pressurized water stream generated by pumps that are capable of pumping an abrasive charged water supply at high rates of speed. The Hydro Systems are good for conveying very fine abrasives. They are also used in cleaning gunky, greasy parts, and containing toxic materials. The wet blast systems are very good at blasting surfaces without damage and blasting internal surfaces.

delivery Systems (Air or Wheel Blasting) Containment Systems (Hand cabinets, Automated enclosures, and Blast rooms) Reclaim Systems dust Collection

containment SyStemS

Hand cabinets, automated enclosures and blast rooms are built to handle various size and shapes of parts. The containment systems are built to control and contain the blast media and parts within the enclosures.The enclosure systems use gravity for the blasted media to drop down to a collection area so the media can be conveyed to the reclaim system. Blast systems can have inexpensive or premium containment systems. Matching the right containment system to the application is very important.

media reclaim SyStemS

Recoverable medias used in industrial blast systems will run from 5 to 100 times through the blast system. These recoverable medias need to be cleaned, sized and returned to the blast system after being blasted. The media reclaim system accomplishes this. The reclaimer keeps finish and production rates consistent. Media reclaim systems can be Air Cyclones or Mechanical Systems.

duSt collection

All Industrial blast systems utilize dust collectors to allow blast systems to be indoors. The dust collector removes the fine blasting dust keeping the media clean and operators safe through visibility and breathable air. dust collectors remove 99% of 1 micron or larger material. Hepa filters can be added to remove dust particles down to 1/2 micron.dust collectors are sized to the cabinet size, media type, and amount of blast nozzles or wheels being used.



blasT meDias

Recoverable blasting medias are used in industrial blasting. Indoor blasting systems require medias with extended life. Blast media, type, shape, size and hardness affect the process and materials they are capable of blasting. Spherical medias are used for peening and produce smoother surface finishes. Angular medias chip at a parts surface; removing paint, rust and scale quicker, with better results than round medias. Angular medias produce a rougher surface finish and produce superior anchor patterns for paint and coating adhesions. Higher blast pressures increase production but reduce media life. Blasting harder workpieces also reduces media life.Recoverable blasting medias have two basic shapes. Round (spherical) and angular.

The most common recoverable industrial blast medias are :

SPherical ShaPed media angular ShaPed media

aluminum oxide (al2o3) is a man made fused alumina that is very tough and angular blocky shaped, medium density, with a hardness of 9 on the Mohs scale. This abrasive is designed for high blasting pressures up to 90 PSI. Aluminum oxide is very good for light deburring and surface prep (bonding strength) prior to painting and coating. AO creates a dull matte finish.Aluminum oxide has media life of approximately10-12 times through the blast system.

ceramic beads aluminum oxide silicon carbide

ceramic grit stainless grit

crushed glass steel grit

glass beads

stainless shot

grit size conversion for ao and sic

tyPical aluminum oxide blaSting aPPlicationS Cleaning of investment castings Scale removal Thermal spray coating preparation Rust removal Hard oxide removal Heat treat and mill scale removal Glass frosting and etching Monument lettering and carving Aircraft engine overhaul Matte finishing Surface preparation durability up to 20 passes

grit size

inches (average)

microns (average)

70 0.008 203

80 0.0085 165

90 0.0057 145

100 0.0048 122

120 0.0048 102

150 0.0035 89

180 0.0030 76

220 0.0025 63

grit size

inches (average)

microns (average)

16 0.043 1092

20 0.037 942

24 0.027 686

30 0.022 559

36 0.019 443

46 0.014 356

54 0.012 305

60 0.010 254



tyPical Silicon carbide blaSting aPPlicationS Blasting hard metals Glass etching Ceramic recast removal Very tough scale removal Heavy profile and metal preparation Before brazing and weld applications requiring

no aluminum oxide contamination

glass beads and glass grit are glass beads used in peening and surface finishing on tight tolerance machined surfaces. Glass Beads create a bright matte surface finish with no surface contamination or damage. As a round particle beads are very slow on removal of paint, rust, or scale. Glass grit is the angular counterpart of glass beads. Glass grit is very aggressive on a blasted surface. Glass beads are blasted at pressures between 40-80 psi. Glass bead media life cycles are 9 - 12 times thru the blast system.

tyPical glaSS bead blaSting aPPlicationS

ceramic blast media ceramic beads are spherical shaped media with high mechanical strength and high wear rates. Ceramic is impact resistance creating very little dust. The ceramic beads keeps its round consistency and is chemically inert. Ceramic blast processes produce a smooth bright satin finish. The ceramic beads density creates higher impact speed making it a good choice for deburring and peening. Blast pressure recommendations are between 40-65 psi with media cycle lives between 70-90 times thru the blast system. Ceramic blast media is very versatile and can be blasted with all delivery systems( air, wheel and water). Ceramic beads is a standard peening material for titanium parts. ceramic grit is angular and is excellent for etching parts with extended media life.

tyPical ceramic media blaSting aPPlicationS

Peening Titanium Non contamination High impact for deburring Long media life applications Bright surface finish requirements Aircraft and medical parts

grit size conversion for ao and sic

SIzING : SAME AS ALUMINUM OxIDE

blasT meDias (conT’D)

silicon carbide (sic) is a man made abrasive that is very sharp and friable. SIC is very hard at 9.5 on the mohs scale. It is used to blast very hard materials such as tool steels, glass and ceramics. SIC creates a dull matte finish. The grit sizes available are the same sizes as aluminum oxide. SIC blasts at pressures up to 90 psi and has an approximate life of 9-12 times thru the blast system.

grit size conversion for glass beads

mil-g- 9954a

inches (average)

microns (average)

us screen size(mesh)

# 3 .0282 725 20-30

# 4 .0187 512 30-40

# 5 .0139 363 40-50

# 6 .0105 256 50-70

# 7 .0084 215 60-80

# 8 .0071 181 70-100

mil-g- 9954a

inches (average)

microns (average)

us screen size(mesh)

# 9 .0060 153 80-120

# 10 .0047 120 100-170

# 11 .0039 100 120-200

# 12 .0033 85 140-230

# 13 .0026 68 170-325

Light deburring. Surface cleaning. Peening. Blending machine marks. Removal of welding discolor. Blasting tight tolerance parts. Produces a bright matte finish. Pre Anodize finishing.



stainless steel blast media is available in both shot (cut wire conditioned and casted) and grit. Stainless media is available in 302-304 and 316 alloys. Stainless is a softer but heavier media that is a good choice for short blasting times, deburring, and rust free surfaces. It produces a brighter finish with reduced blast machine wear rates. stainless shot obtains some the highest media recovery rates of up to 150-200 cycles through the blast system. Blasting pressure can be as high as 90 PSI.

tyPical StainleSS Steel blaSting aPPlicationS

Blast cleaning, deburring, surface refinement, surface finishing All types of aluminum castings and forgings Zinc pressure die castings Non-ferrous metals and special alloys Stainless steel castings and forgings Stainless steel equipment fabrication Granite and stone industry

steel shot and grit media is produced in round/spherical shape (conditioned cut wire and cast shot) and angular steel grit. Steel abrasives are very durable making it the first choice in blast rooms and automated wheel applications. The hardness ranges between 40 to 65 Rockwell. Conditioned cut wire (rounded) is the primary choice for shot peening over cast shot that produces an unfavorable angular breakdown while blasting. Steel shot and grit is very often mixed to achieve both anchor patterns with good finishes. Steel shot can be blasted with very high pressures ofup to 110 PSI. Media cycle lives are between 80-100 times through the blast cycle.

tyPical Steel Shot and grit blaSting aPPlicationS

Blast Rooms for long media life Wheel blasting for long media life Paint preparation on steel parts deburring Scale and rust removal Aluminum Casting and weldment blasting Pipe blasting (Id & Od)

BLAST MEdIAS (CONT’d)



BLAST MEdIAS (CONT’d)

sTeel shoT

s390

All Pass No. 12 Screen .0661- 1.70

5% Max on #14 Screen .0555 - 1.40

85% Min on #18 Screen .0394 - 1.00

96% Min on #20 Screen .0331 - 0.850

s330

All Pass No. 12 Screen .0555 - 1.40

5% Max on #14 Screen .0469 - 1.18

85% Min on #18 Screen .0331 - 0.85

96% Min on #20 Screen .0278 - 0.710

s280


5% Max on #18 Screen .0394 - 1.00

85% Min on #25 Screen .0278 - 0.710

96% Min on #30 Screen .0234 - 0.600

s230

All Pass No. 18 Screen .0394 - 1.00

10% Max on #20 Screen .0331 - 0.85085% Min on #30 Screen .0234 - 0.60097% Min on #35 Screen .0197 - 0.500

s170


10% Max on #25 Screen .0278 - 0.710

85% Min on #40 Screen .0165 - 0.425

97% Min on #45 Screen .0139 - 0.355

s110


10% Max on #35 Screen .0197 - 0.500

80% Min on #50 Screen .0117 - 0.30090% Min on #80 Screen .0070 - 0.180

sTeel griT

g25All Pass on #16 Screen .0469- 1.18

70% Max on #25 Screen .0278 - 0.710

80% Min on #40 Screen .0165 - 0.425

g40All Pass on #18 Screen .0394 - 1.00

70% Max on #25 Screen .0165 - 0.425

80% Min on #40 Screen .0117 - 0.300


65% Max on #50 Screen .0017 - 0.300

70% Min on #80 Screen .0070- 0.180


60% Max on #80 Screen .0070 - 0.180

75% Min on #120 Screen .0049 - 0.125

g120All Pass on #50 Screen .01117- 0.300

60% Max on #120 Screen .0049 - 0.125

70% Min on #200 Screen .0029 - 0.075

shot And grit sizing



BLAST MEdIAS (CONT’d)MEDIA OvERvIEW :

recoverable blasTing meDias

general meDia informaTion

angular ShaPed media

media guide

SPherical ShaPed media

Ceramic Beads

AluminiumOxide Garnet Plastic

MediaCeramic

GritCrushed

GlassSilicon

CarbideStainless

GritSteelGrit

WalnutShells

Glass Beads

StainlessShot

SteelShot

Glass Beads

CeramicGrit

StainlessCut Wire

SteelShot

SteelGri

Alumi-niumOxide

SiliconCarbide Garnet Crushed

GlassPlasticMedia

WalnutShells

Finishing Yes Yes Yes Yes Yes Yes Yes Yes Yes no noCleaning/Removal Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

Peening Yes Yes Yes Yes no no no no no no noSurface Profiling (Etch) no no Yes no Yes Yes Yes Yes Yes Yes Yes

Working Speed MED. MED. MED. MED. MED.-hiGh hiGh vERy hiGh hiGh hiGh MED.-hiGh LOW-hiGhRecyclability hiGh-LOW hiGh hiGh vERy hiGh vERy hiGh MED.-hiGh MED.-LOW MED. MED.-LOW MED. LOW

Probability of Metal Removal vERy LOW vERy LOW vERy LOW vERy LOW MED. MED.-hiGh MED.-hiGh MED. LOW-MED. vERy LOW vERy LOWhardness, MOh Scale

(Rockwell RC)5.5 7

(57-63)6-7.5

(35-55)6-7.5

(35-55)8-9

(40-66)8-9 9 8 5.5 3-4 1-4.5

Bulk Density (lb/cu.ft.) 100 150 280 280 230 125 95 130 100 45-60 40-80Mesh Size 30-

4408-46 20-62 8-200 10-325 12-325 36-220 16-325 30-

40012-80 manY

Typical Blast Pressure 20-55 20-90 20-90 20-90 20-90 20-90 20-90 30-80 20-50 20-60 10-40Shapes : or or

* Above information is intended as a general reference guide

Spherical Medias are used for peening and produce smoother surface finishing.

Angular medias chip at a part surface removing paint, rust, and scale quicker than round medias and produce a rougher surface finish and better anchor patterns for coating adhesions.

Higher blast pressures reduce media life.

Higher blast pressures increase production.

Harder work pieces reduce media life.

dust collection keeps media clean.

When calculating media — take in account.

Media cost and life cycles.

disposal fees (if blasting heavy metals use a very rercyclable media)

Production rate of media, labor and air compressor expense.



BLAST MEdIAS (ENd)

recoverable meDia cYcles

recoverable meDia cosTing

overvieW of blasT finishing eQuipmenT anD abrasive meDias

media Type media life cycles % breakdown

SILICA SAND 1 100 %

GARNET 3-5 25 %

PLASTIC MEDIA 7-9 13 %

GLASS BEAD 9-12 10 %

SILICON CARBIDE 9-10 11 %

media cost per hour media cost to blast a part

Hourly Delivery Rate x % Breakdown x Cost per lb

Hourly Delivery Rate x % Breakdown x Cost per lb x Part cycle time (% of hour)

eQuipmenT abrasive meDias

Air blasting Spherical

Blast cabinets Glass beads

Automated cabinet Ceramic beads

Blast rooms Steel shot

Portable pressure pots Stainless shot

ID-OD pipe blasters Angular

Basket blasters Aluminum oxide

In line conveyors Ceramic grit

eQuipmenT abrasive meDias

Wheel Blasters Glass grit

Spinner hangers Plastic stripping media

Table blasters Steel grit

Conveyor blasters Stainless steel grit

Basket blasters Silicon carbide

Wet Blasting cabinets Media + Water

Soda blasting Baking soda

Dry ice blasters Dry Ice

media Type media life cycles % breakdown

ALUMINUM OxIDE 10-12 9 %

CERAMIC MEDIA 70-90 1.2 %

STEEL SHOT, GRIT 80-100 1 %

STAINLESS SHOT, GRIT 150-225 0.5 %

Other factors in total blasting cost include : air compressors, labor, blast system costs and media disposal fee. If blasting heavy metals use a highly recyclable media.



HOW TO MEASURE SURFACE PROFILE USING TESTEx TAPE

TesT preparaTion

perform The TesT

measuring The TesT resulT

sources of error

� Select a representative test site free of dust, dirt and pitting. � Choose the appropriate grade of Testex tape – refer to Inspection Instruments for details of the various

scale measurement ranges. � Peel a test tape strip from the roll – a ‘bull’s-eye’ marker dot will remain on the slip paper. � Apply the tape to the test surface – rub over the tape with afinger to ensure it is firmly adhered.

� Using moderate to firm pressure, rub the test window with the round-tip burnishing tool � Take care not to dislodge the test tape (caused by bumping the tool against the edge of the circular cutout

window). � Burnish the test window until it has uniformly darkened – the color indicates the profile has been impressed

into the test tape. � Peel the test tape strip from the surface.

� Use a dial thickness gage with the correct specifications (i.e. accuracy, anvil spring pressure and anvil size) for replica tape – refer to Inspection Instruments

� Clean the anvils and check/adjust the zero point. � After cleaning and checking the gage zero point, adjust the dial to minus 2 mils (50 microns) (this compensates

for the thickness of the tape carrier film and allows the profile measurement to be read directly from the gage). � Centre the test tape between the anvils, gently allow the anvils to close on the tape, and note the reading on

the dial. � Take several readings to establish accuracy. (Reposition the tape in the anvils between each reading).

� Inherent Profile Variation in the surface – perform at least 3 tests per 100 square feet (10 square metres) of area. � Contaminant particles in the anvils or tape – select a clean surface; clean and check the anvils; examine the test

tape; double check any questionable readings. To indicate the size significance of seemingly tiny contaminants, please note that human hair is approx. 2 mils (50 microns) thick.

� Improper Gage – a good gage has an accuracy of ±0.2 mils (±5 microns), closing force of 1.5N and at least one anvil 0.25” (6.3mm) diameter.

� deficient Impressing Technique – use a profile training tool to verify the burnishing technique is correct.

There are four major sources of error in determining the profile of a blast cleaned surface, which can be minimized with thefollowing suggestions.

step 1 step 2 step 3


www.istblast.com www.istsurface.comT : 1 877 629-8202F : 450 963-5122 20

17-1

1-09

ISTblast est une marque de commerce

enregistrée de International Surface Technologies

4160, boul. IndustrielLaval, QuébecH7L 6H1 Canada

WHO WE ARE

IST is a leading industrial manufacturer of standard and custom engineered equipment for the surface treatment industry and the solvent recycling industry.

MISSION

IST is dedicated to being an innovative and trusted supplier in the conception, fabrication and distribution of surface treatment equipment and recycling equipment.The success of our mission relies on the following core values :

Innovation - Integrity - Quality

MARkETS SERVEdThe products, technologies and industry expertise of IST are used in a wide range of manufacturing and industrial applications, including but not limited to :

• General Manufacturing

• Industrial Equipment

• Metal forming

• Aerospace and Aviation

• Rail and Transit

• Marine

• Automotive

• Petroleum

• Flexography (labelling) & Lithography

• Wood finishing

• Power & Energy

• Pharmaceutical

OUR MISS ION

...Blasting is the process where small angular or spherical particles are propelled at a part by compressed air, or mechanical high speed rotating wheels or water pumps. The blast

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